It’s the one thing that no other living group of species has, feathers. They are viral for a birds survival, they provide insulation, flight, and aid in courship. From feathers you can tell an individuals species, and sometimes its age and sex. They can form patterns and affect what their body shape looks like, to hide from predators or be flashy to attact a mate. But what are they Really made of? At the most basic level feathers are keratin structures, the same thing your hair and nails are made of.
These structures can be broken down into 6 basic designs. Each feather type has a different purpose and a different design. These basic forms can be called flight, contour, semiplume, filoplume, bristle and down feathers.
Flight Feathers:
Can be further broken down into remiges (wing feathers) and rectrices (tail feathers). These feathers are specialized for flight, characterized by being long, stiff and asymmetrical.
Contour Feathers:
These feathers are the main feathers that cover the body and cover the edges of the flight feathers. They help make birds more aerodynamic by helping to form the airfoil for flight and waterproofing. These are the feathers that give a bird their apearance, to attract a mate, to hide from a predator, they can form patterns.
Semiplumes:
An underlaying structure hidden under the contour feathers. These create an additionalal fluffy layer of feathers to aid in insulation.
Filoplumes:
Short feathers with very few barbs, these act similar to the whiskers on a cat and will sense the position of surrounding contour feathers. This can help the bird tell when the contour feathers are out of place and they need to preen.
Bristle Feathers:
The most simple of all the feather groups, consists of a strong rachis without any branches. The best example of this can be seen on flycatcher and owl species. Being found around a birds beak and face, they aid in protecting their eyes and face and is the case with flycatchers and other birds aiding in catching insects in the air.
Down Feathers:
The shortest feathers and the ones closest to the body. As with semiplumes they apear very fluffy and aid in insulation by trapping body heat.